const b = require('./moduleCount');

try{          
    console.log(b.handle(4,5,'add'));       // 9
    console.log(b.handle(5,5,'subtract'));  // 0
    console.log(b.handle(4,5,'multiply'));  // 20
    console.log(b.handle(10,2,'divide'));   // 5
    console.log(b.handle('a','b','add'));   // 非数值情况
}catch(error){                   //捕获
    console.log(error.message)
}          